Correct spelling for SHOULLD

We think the word shoulld is a misspelling.
It could be just an incorrect spelling of the words which are suggested below.
Review the list and pick the word which you think is the most suitable.
For your convenience, we put a usage example below each word

We have no right to have our dressing station where it is, we have dumped ourselves down, and have erected our largest red cross flag, in front of several closely packed lines of reserve trenches, which is contrary to the rules of warfare, and if we get shelled it is our own lookout.